Hydraulic fracturing is a stimulation treatment routinely performed on oil and/or gas wells. “Fracturing” refers to the method of pumping a fluid into a well until the pressure increases to a sufficient level to fracture the subterranean geological formations. A propping agent or “proppant” is injected, along with a hydraulic fluid, into the wellbore to maintain open the newly formed fractures extending from the wellbore in generally opposing directions. The proppant remains in place once the hydraulic pressure is removed and therefore props open the fracture to enhance flow in the wellbore.
Proppants can be made of virtually any generally solid particle that has sufficient particle strength, sphericity and size. Silica-containing material, like sand, and ceramic materials have proved to be especially suitable for use in hydraulic fracturing.
Typically, in any hydraulic fracturing system, a large amount of such proppant is required. Increasing technology and improved techniques have resulted in the use of greater volumes and higher concentrations of proppant in hydraulic fracturing systems in the oil field. This increased use of proppant has created the demand for more dependable proppant handling equipment capable of moving large amounts of proppant from on-location storage units to a blending apparatus with little or no spillage. The equipment must also provide a steady, even flow of proppant to the blender to prevent fluctuations in the concentration rates pumped down into the wellbore.
It can be difficult to effectively transport proppant, or some other material, to a desired location at a steady flow rate with little or no spillage. Typically, transportation of the proppant occurs by a conveyor at some predetermined volumetric flow rate. The volumetric flow rate transferring the proppant must be tightly coordinated with the volumetric flow rate of the proppant exiting the conveyor. If the proppant exits the conveyor at a volumetric flow rate less than the rate at which it is being transferred, proppant buildup occurs. Monitoring the proppant buildup to prevent spillage typically requires either human interaction or a complex electronic or hydraulic system comprising sensors and control components.